[FFmpeg-devel] [PATCH] avformat/matroskaenc: add reserve free space option

[Dave Rice]

> On Sep 12, 2018, at 11:56 AM, Sigríður Regína Sigurþórsdóttir <siggaregina at gmail.com> wrote:
> 
> On Thu, Sep 6, 2018 at 3:31 PM James Almer <jamrial at gmail.com <mailto:jamrial at gmail.com>> wrote:
>> 
>> On 9/6/2018 4:18 PM, James Darnley wrote:
>>> On 2018-09-06 19:39, Sigríður Regína Sigurþórsdóttir wrote:
>>>> +    if (s->metadata_header_padding) {
>>>> +        if (s->metadata_header_padding == 1)
>>>> +            s->metadata_header_padding++;
>>>> +        put_ebml_void(pb, s->metadata_header_padding);
>>>> +    }
>>> 
>>> Unfortunately I was forced to make the default -1 so you want to check
>>> that the value is greater than 0 rather than just true.
>>> 
>>> Furthermore I think you will still want to add to Changelog making a
>>> note that the matroska muxer will now listen to metadata_header_padding.
>> 
>> No, this kind of change doesn't justify a Changelog entry as mentioned
>> before.
>> 
>>> That may also want a micro version bump so that library users can check.
>> 
>> Micro version bump is ok.
> 
> 
> Thank you.
> 
> Here is an updated patch with a bump and a change to make sure the value is > 0.
> 
> 
> 
> From 08e140fa0b23274a4db18ce0b201e45fe7c1ac97 Mon Sep 17 00:00:00 2001
> From: Sigga Regina <siggaregina at gmail.com <mailto:siggaregina at gmail.com>>
> Date: Wed, 12 Sep 2018 11:47:47 -0400
> Subject: [PATCH] avformat/matroskaenc: add reserve free space option
> 
> ---
> libavformat/matroskaenc.c | 5 +++++
> libavformat/version.h     | 2 +-
> 2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c
> index 09a62e1..3f5febf 100644
> --- a/libavformat/matroskaenc.c
> +++ b/libavformat/matroskaenc.c
> @@ -2005,6 +2005,11 @@ static int mkv_write_header(AVFormatContext *s)
>         ret = AVERROR(ENOMEM);
>         goto fail;
>     }
> +    if (s->metadata_header_padding > 0) {
> +      if (s->metadata_header_padding == 1)
> +        s->metadata_header_padding++;
> +      put_ebml_void(pb, s->metadata_header_padding);
> +    }
>     if ((pb->seekable & AVIO_SEEKABLE_NORMAL) && mkv->reserve_cues_space) {
>         mkv->cues_pos = avio_tell(pb);
>         if (mkv->reserve_cues_space == 1)
> diff --git a/libavformat/version.h b/libavformat/version.h
> index 4d21583..d7a1a35 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -33,7 +33,7 @@
> // Also please add any ticket numbers that you believe might be affected here
> #define LIBAVFORMAT_VERSION_MAJOR  58
> #define LIBAVFORMAT_VERSION_MINOR  18
> -#define LIBAVFORMAT_VERSION_MICRO 100
> +#define LIBAVFORMAT_VERSION_MICRO 101
> 
> #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
>                                                LIBAVFORMAT_VERSION_MINOR, \
> -- 
> 2.10.1 (Apple Git-78)
> <0001-avformat-matroskaenc-add-reserve-free-space-option (1).patch>_______________________________________________

ping on this, as reserving such space in Matroska headers for later edits to the Tracks element would be helpful.
Dave Rice